Already today there is an enormous amount of end user stations, or network terminals, used for many different purposes. In the future there will be even more and more network terminals also for other, future, purposes. Examples on end users stations are mobile phones, PDAs (Personal Digital Assistants), computers, Laptops, Palm tops, cable-TV modems, X-DSL modems, intelligent networked appliances, wireless web pads etc. In other words, enormous amounts of network devices are expected in the near future. However, all these network terminals or end user stations need to be addressable. In general each network terminal or end user station must have its own unique, public IP-address. This is particularly important in order to be able to realize the vision of “always on”, “always connected”, and “always reachable” from anywhere. In the future there will also be more and more different networks which all are connected with each other, such as company networks, broadband access networks, residential networks, cellular networks, wireless networks, local networks etc.
Until now the Internet has been based on the IP-protocol version 4, IPv4, addressing scheme. The IP-protocol version 4 uses a 32-bit address in the form of [IP-address-XXX.XXX.XXX.XXX/subnet mask-XXX.XXX.XXX.XXX]. However, the available address space of IPv4 will soon have come to an end and there will not be enough unique IP-addresses left to handle out for a new operator or for new types of end user stations or for more devices in general. Even if technologies such as private IP-address networks in combination with NAT (Network Address Translation) and different types of proxies are used, this would not be enough.
Therefore the new addressing scheme, IP version 6, has been suggested. IPv6 uses a 128-bit address base. This means that the address length is four times that of IPv4. The IPv6 basic specification includes in addition thereto security and it includes packet encryption, ESP (Encapsulated Security Payload) and source of authentication, AH (Authentication Header).
Other advantages of IPv6 is that, in order to support for real time traffic such as video conferences, IPv6 has a “flow label”. Using flow labeling, it gets possible for a router to know which end-to-end flow a packet belongs to, and then to find out which packets belong to the real time traffic class. Moreover the basic specification of IPv6 includes an address auto-configuration facility. This means that even a novice user can connect his machine, or the end user station, to the network. It may also implement a specification optimisation in that it discards old and useless parts of IPv4 whereas it keeps with useful parts of IPv4. Moreover it includes support for mobile Internet.
Work is in progress within 3GPP standardisation Release 5, to introduce IPv6 in the 3GPP standards. IPv6 as specified within IETF (Internet Engineering Task Force) standard body does in general not take any special consideration to the specific environment in the cellular/wireless domain, e.g. as far as the radio resources are concerned, and as far as power consumption of the terminal is concerned. The known solution of IPv6 address autoconfiguration is described in IETF RFC (Request For Comments) 2461, which herewith is incorporated herein by reference. In this document the algorithm for sending first initial Router Advertisements (RA) from a router to an end user station is described. Generally the constants controlling the sending of RA are set so that three initial RAs are sent with 16 seconds interval.
After the initial phase, a router (e.g. GGSN), (Gateway GPRS Support Node,) shall start to send RAs periodically, default one RA approximately every 10 minutes. It should be noted that the IETF standard, e.g. the RFC 2461, leaves it open to specify specific values on their specified constants for specific “links”. The connection between a mobile terminal and the GGSN is one specific link. It should also be noted that the mobile terminal needs the RA to be able to create its IPv6 address. The RA contains the “Prefix” which is the first part (64 bits) of the 128 bit IPv6 address. The mobile terminal takes this prefix, adds a 64 bit suffix (which in the 3GPP case could be a random number), and then it has its global (or site-local) IPv6 address and can start to communicate. The problem is that the RAs are not sent frequently enough during the initial phase resulting in a slow set up of the GPRS of 3G packet/IP connection to Internet or Intranet. End users do not want to wait for for example 15 seconds before they can start to use the page they have requested on their mobile phone, or start the video/multimedia-phone-call after they have dialled the number. The general wish is to be able to push the button and then expect a response within one or a few seconds. The problem with just setting the RFC 2461 specified parameters to a value allowing these frequent RAs (e.g. at intervals of 1,2 or 3 seconds, is that during the first minute, far to may RAs will have to be sent over the radio interface, perhaps 30 or more. That will consume radio resources and also processing resources in 3G nodes, like GGSN, SGSN, RNC and Node B, not for one but for every PDP context that is initiated (cf. 3GPP TS 23.060; “General Packet Radio Service (GPRS); Service Description of Stage 2, which herewith is incorporated herein by reference). Setting the parameters so that fewer RAs will be sent, will on the other hand result in a long response time for the end user.